Adjustable fit pack frame

ABSTRACT

A pack frame that is adjustable in length to position the shoulder bar, upper back band, and side arms of the device in the appropriate spaced relationship to fit a particular user. The length adjustment includes telescoping tubes for the main side rails and the central structural rods of the device. Adjustment is also provided for the space between the side arms and the angle of the side arms. Finally, adjustment is provided in the load transfer point for the upper portions of the shoulder straps. The shoulder straps are free to move at their upper point, to seek the proper position. The shoulder straps are secured to the central rod by oversized grommets.

United States Patent [191 Mead et al.

[11] 3,827,612 [451 Aug. 6, 1974 ADJUSTABLE FIT PACK FRAME [21] App].No.: 292,151

2/1954 France 224/8 R 2/1918 Sweden 224/8 R Primary Examiner-Robert J.Spar Assistant Examiner-Jerold M. Forsberg Attorney, Agent, orFirm-Brown and Martin [5 7] ABSTRACT A pack frame that is adjustable inlength to position the shoulder bar, upper back band, and side arms ofthe device in the appropriate spaced relationship to fit a particularuser. The length adjustment includes telescoping tubes for the main siderails and the central structural rods of the device. Adjustment is alsoprovided for the space between the side arms and the angle of the sidearms. Finally, adjustment is provided in the load transfer point for theupper portions of the shoulder straps. The shoulder straps are free tomove at their upper point, to seek the proper position. The shoulderstraps are secured to the central rod by oversized grommets.

7 Claims, 4 Drawing Figures ADJUSTABLE FIT PACK FRAME It has longbeenrecognized that the fit of a pack frame is' extremely important to thecomfort of the user. That is, the pack frame must be sized correctly fora particular user, to transfer weight to the user at the appropriateplaces on his frame and to balance the load properly in relationship tothe users center of gravity.

Obtaining such a fit from an existing pack frame has been a matter oftrial and error. Many individuals with undersized or outsized shapescould not be satisfactorily fitted by any available pack frame. Poorlyfitted pack frames do not place the load properly over the users centerof gravity, and result in an excessive pull on the shoulder straps. Theresult is an uncomfortable walking position and abrasion from thestraps.

Thus, it is desirable to have a new and improved pack frame design thatprovides for sufficient adjustment in the overall length of the packframe, as well as the particular attachment point to the users body,such that substantially all users, despite their shape or size, may beproperly fitted to the frame. Such a pack frame is particularlydesirable where the contact points with the user were padded andarranged to minimize abrasive contact.

SUMMARY OF THE INVENTION An exemplary embodiment of the inventionincorporates a pack frame having telescoping side rails, as well ascentral rod members, that allow for longitudinal adjustment. The siderails may be telescoped to extend or retract the distance between theside arms and shoulder bar. The side rails may be retained in anyselected position. By this adjustment, the proper space relationshipbetween the side arms, and its associated hip hugging pad, from theshoulder bar and its associated upper back band, may be established. Inthis manner, the load will be carried as high on the user as isdesirable, and the cushioning of the back band will be provided at theappropriate place. The vertical adjustment is accommodated, and theeffectiveness of the shoulder straps are accentuated by the design ofthe invention, whereby the upper ends of the shoulder strap have aselected amount of vertical adjustment. In the exemplary embodiment, thevertical adjustment is accomplished by securing the shoulder straps onthe central bars by oversize grommets. The oversized grommets allow theupper end of the shoulder strap to seek its appropriate verticalposition. Once stabilized in this position, it will not movesignificantly under load.

Adjustment is also provided for in the lower back band or hip huggerpad. The overall width of the user is compensated by the side arms beingbent until the appropriate width is attained. Various lengths of lowerback bands compensate for the users width.

It is therefore an object of the invention to provide a new and improvedadjustable fit pack frame.

It is another object of the invention to provide a new and improvedadjustable pack frame that is adjustable in overall height.

It is another object of the invention to provide a new and improvedadjustable pack frame that accommodates a variety of width and shapes ofusers.

It is another object of the invention to provide a new and improved packframe that accommodates vertical adjustment in the upper ends of theshoulder strap.

It is another object of the invention to provide a new and improvedadjustable pack frame that is relatively low in cost.

It is another object of the invention to provide a new and improvedadjustable pack frame that does not add significantly to the weight ofthe structure nor reduce its overall strength.

Other objects and many attendant advantages of the invention will becomemore apparent upon a reading of the following detailed description,together with the drawings, in which like reference numerals refer tolike parts throughout and in which:

FIG. 1 is a perspective view of the pack frame of the invention.

FIG. 2 is a planar view of the pack frame taken from the back sidethereof.

FIG. 3 is an elevational view taken along lines 3-3 of FIG. 2.

FIG. 4 is a sectional view of the back pad of the invention taken alonglines 44 of FIG. 3.

Referring most particularly to FIGS. 2 and 3, the adjustable pack frameof the invention is illustrated to comprise a frame portion 10,including side rails 12 and 14. The structural cross members on theframe include a shoulder bar 28, and tubular horizontal frame members30, 32, and 34. A pair of side arms 36 and 38 are mounted at the lowerend of the frame, and carry between them a padded back band or hiphugger 54.

The main side rail members 12 and 14 are bent, substantially at thelocation of the shoulder'rail. The purpose of this bend is to cause thehighest portion of the load to be carried toward the center of gravityof the user. The horizontal cross members of the pack frame are utilizedfor rigidizing and adding structural strength to the pack frame and alsoto accommodate the free ends of the side arm 36 and 38. Each of thecross members 30, 32 and 34 is bent adjacent to each end, to positionthe cross members and the vertical rod members away from the plane ofthe frame as defined by the shoulder bar and side rails. This spacingprevents any contact between the load and the users back or other bodyportion. A fabric upper back band 50 is secured across the upper frontportion of the frame below cross bar 28, and is held tightly stretchedaround the side members 12 and 14 by tie cords 52. The structuralmembers'of the pack frame in the instant embodiment are primarily ofaluminum tubular and rod construction. However, any high strength, lowweight, material could also be employed within the scope of theinvention.

Referring to the pack frame details illustrated in FIGS. 1 and 2 in moredetail, the horizontal cross members, are receivedwithin bores in thevertical side rails. The shoulder bar is secured to the vertical railsby surface welding. The side rails 12 and 14 also receive the lower siderail telescoping portions 16 and 18. These are received within the upperside rails, and positioned in the upper side rails by a pair of clevispins 20 and 22. The clevis pins are received through the upper side railmembers and through a selected bore, of a plurality of vertically spacedbores, in the lower side rail telescoping members. In this manner, byremoval of the clevis pins 20 and 22, the overall length of the packframe may be adjusted to substantially any desired length, and thedesired length retained by reinserting the clevis pins 20 and 22 in theappropriate bore in the lower telescoping members. After properadjustment is established,

the clevis pins 20 and 22 are retained in position by the use ofretainers 24 and 26. The telescoping action of the main side railmembers is accommodated by the central rod members 88 and 90 by theirbeing slidably received through cross member 30, and telescopicallyreceived within slip tubes 92 and 94. Since the overall length of theframe is fixed by the clevis pins 20 and 22, the slip tubes need nothave any provision for fixing the adjustment and accommodate the centralrod members in a frictional slipping engagement. The slip tubes arereceived in the shoulder rail, at a lesser spaced-apart distance thanthe spaced apart distance for the lower portions of the vertical rodmembers in the cross member 34. This spacing permits the slip tubes toserve as attachment structure for the shoulder straps as will be morefully described hereinafter.

The side arm configuration illustrated in FIGS. 1 and 3 includes agenerally U-shaped member of a bendable heavy wall tubing or rodmaterial 36 and 38. This side arm material is of an alloy whichmaintains enough rigidity and spring to not bend in normal use yet whichallows bending to alter width between the side arms. Side arm 36 istypical and includes an upper rod portion 40 and lower rod portion 42.Side arm 38 comprises upper rod portion 44 and lower rod portion 46.Referring to FIG. 3, the terminal portion 48 of the upper rod portion 40is received through the lower telescoping side rail member 16 and intothe'inner diameter of the cross member 32. Thus, the side arms arereceived within the cross member slidably and are frictionally held inposition by forcing the upper and lower rod portions into the curvedportions of the cross members 32 and 34. Vertical attachment members 81and 83 are provided between the upper and lower guide members of theside arms 36 and 38, respectively, and may include adjustment holes suchas hole 85, to accommodate vertical adjustment of the pack attachment.The strap attachment 56 is illustrated as being secured by a bolt andnut 82 to the vertical attachment member 81. The strap 56 is secured toits corresponding vertical attachment member by a nut and bolt 84. Abuckle 60 is provided to secure the free ends of the strap around theuser.

Referring most particularly to FIGS. 1 and 2, there is illustrated apair of padded shoulder straps 96 and 98 with adjustable lower strapportions 108 and 110. The lower strap portions are secured to thehorizontal bar 34 at 109 and l 11. The padded straps 96 and 98 aresecured, through grommets 100 and 102, to the slip tubes 92 and 94. Theupper straps are free to slide along the slip tubes as determined on thetensioning on the shoulder straps. The position of the upper strapsstabilizes under load because the primary load transferred by the strapsis carried through the lower strap portions 108 and 110 and the upperstraps are substantially horizontal. Friction between the grommets 100and 102 and the slip tubes holds them in position, so they do not shiftunnecessarily. A pair of sleeves 104 and 106 is received over the sliptubes and frictionally engages thereon, to limit the vertical travel ofthe shoulder straps, so that the upper end of the shoulder straps do notslide down the slip tubes an excessive distance when the frame isresting on the ground.

The upper portion of the shoulder straps and the lower back band or hiphugger, are of a padded construction that contributes importantly to thefunctioning of the invention. The design of this padded construction ismost apparent from'the illustration in FIG. 4. A first pad layeriscomprised of a locked cell foam material. By utilizing locked cell foam,the cushioning effect is insured. This type of foam cannot crush flatand retains a progressively stiffer cushioning effect as it iscompressed. The padding is doubled in the area of theattaching bolt. Asecondpad layer 72 is provided. The material incorporated in layer 72 isa Dacron fiber material and absorbs moisture, in addition to providingpadding. The moisture absorption characteristic is important to thecomfort to the user, in that excessive moisture accumulating on the skinwill cause shaffing and other discomfort. The padded layers areseparated by fabric material 76, and are surrounded by additional layers77 and 79 of this material. These materials are primarily protective innature. The loads carried through the back band and/or shoulder straps,are transferred to a belt webbing 80, or substantially the same materialas the waist belt 58 and 56. Incorporating the belt within the backband, rather than utilizing a continuous waist belt, avoids the tanglingand twisting that is otherwise experienced when utilizing a unitary'belt.

OPERATION In use, the pack frame of the invention is adjusted to theparticular user to rest on and transfer the load, to the users anatomyin the most comfortable fashion possible.

The first adjustment is to bend the side arms in width until they willallow the lower back band to come to rest in the proper location belowthe waist.

The second adjustment is to set the spacing between the lower back band54 and the shoulder bar. The spacing desired, is that which will placethe shoulder bar slightly above the shoulders of the user, at the sametime that the hip hugger, or lower back band is resting on the userships and buttocks. In this operation, the hip hugger is placed over theusers hips, so that the side arm portions of the back band cover the hipbone, and the rear portion of the back band rests on top of the shelf ofthe buttocks. The pins 20 and 22 are unlocked from retainers 24 and 26and removed from the telescoping tubes, whereupon the upper portion ofthe frame is raised or lowered to properly position the shoulder bar.With this bar in its most desired position, the pins 20 and 22 areinserted in the closest bore through the lower side rail tube 18 and 16,and the retainers 24 and 26 again fastened. With the shoulder barproperly located, the upper back band will be against the shoulderblades. This keeps any other part of the frmae from being in contactwith users back. On conventional pack frames with lower bands similar tothe upper back band 50, the lower back hand does not necessarily conformto the users back. Often the load is carried only on the leading edge ofthese lower back bands. In the instant invention, the useof side armsmoves the carry point forward to the users midpoint. This forces theback portion of the hip hugger to tip up until it conforms with theusers back, thus distributing the load over its full surface.

The other adjustments including the tightness of the waistband and theshoulder straps are made by the user and are varied from time to time toachieve maximum effect. With the pack frame on the users back anda loadin place, the upper portions of the shoulder straps 96 and 98 will seeka position along slip tubes 92 and 94, to produce the optimum adjustmentof the angular relationship of the shoulder to the shoulder strap,without further attention from the user.

Having described our invention, we now claim.

1. An adjustable pack frame for transferring the weight of a pack to auser comprising,

a plurality of vertical frame members including adjustment means forselectively varying the length of said vertical frame members, saidvertical frame members comprise two side rails and at least one verticalframe rod disposed between said side rails, said adjustment means forsaid side rails comprises upper and lower side rails,

one of said side rails being telescopically received in the other ofsaid side rails,

means for retaining said upper and lower-side rails in a selectedtelescoped position,

a plurality of horizontal frame members connecting said vertical framemembers at spaced intervals,

a pair of opposed side arms secured to said frame and carrying a paddedback band between said opposed side arms,

a plurality of shoulder straps, each having a first end connected to thelower portion of said frame and a second end mounted for free slidingmovement parallel to said vertical frame members,

said shoulder straps automatically adjust the changing load conditionsso that substantially no vertical load is carried through said shoulderstraps and substantially all of the load is carried by said back band.

2. The adjustable pack frame of claim 1 further including,

a waist belt comprising separable belt sections,

and one end of each of said belt sections being secured to said sidearms.

3. The adjustable pack frame of claim 1 wherein,

said adjustment means for said vertical frame rod comprises a tubetelescopically receiving said rod.

4. The adjustable pack frame of claim 1 wherein,

at least two of said vertical frame rods are received telescopically intubes on opposite sides of the center line of said frame,

and shoulder straps having grommets at their upper ends received oversaid tubes.

5. The adjustable pack frame of claim 1 including,

at least two horizontal frame members comprising tubular members,

said side arms comprising generally Ushaped rods,

and the ends of said rods being received through said vertical framemembers and into said tubular horizontal frame members.

6. The adjustable pack frame of claim 5 wherein,

said side arms are bendable to vary their orientation from said frame.

7. The adjustable pack frame of claim 1 wherein,

said back band comprises a layered padded belt incorporating a layer oflocked cell foam material, an absorbent layer, and an uncoated fabricprotective layer to allow passage of perspiration to the absorbed layer.

1. An adjustable pack frame for transferring the weight of a pack to auser comprising, a plurality of vertical frame members includingadjustment means for selectively varying the length of said verticalframe members, said vertical frame members comprise two side rails andat least one vertical frame rod disposed between said side rails, saidadjustment means for said side rails comprises upper and lower siderails, one of said side rails being telescopically received in the otherof said side rails, means for retaining said upper and lower side railsin a selected telescoped position, a plurality of horizontal framemembers connecting said vertical frame members at spaced intervals, apair of opposed side arms secured to said frAme and carrying a paddedback band between said opposed side arms, a plurality of shoulderstraps, each having a first end connected to the lower portion of saidframe and a second end mounted for free sliding movement parallel tosaid vertical frame members, said shoulder straps automatically adjustthe changing load conditions so that substantially no vertical load iscarried through said shoulder straps and substantially all of the loadis carried by said back band.
 2. The adjustable pack frame of claim 1further including, a waist belt comprising separable belt sections, andone end of each of said belt sections being secured to said side arms.3. The adjustable pack frame of claim 1 wherein, said adjustment meansfor said vertical frame rod comprises a tube telescopically receivingsaid rod.
 4. The adjustable pack frame of claim 1 wherein, at least twoof said vertical frame rods are received telescopically in tubes onopposite sides of the center line of said frame, and shoulder strapshaving grommets at their upper ends received over said tubes.
 5. Theadjustable pack frame of claim 1 including, at least two horizontalframe members comprising tubular members, said side arms comprisinggenerally U-shaped rods, and the ends of said rods being receivedthrough said vertical frame members and into said tubular horizontalframe members.
 6. The adjustable pack frame of claim 5 wherein, saidside arms are bendable to vary their orientation from said frame.
 7. Theadjustable pack frame of claim 1 wherein, said back band comprises alayered padded belt incorporating a layer of locked cell foam material,an absorbent layer, and an uncoated fabric protective layer to allowpassage of perspiration to the absorbed layer.